The present invention relates to a new and improved apparatus and method for use in casting a plurality of articles in a mold structure which is lowered from a furnace.
A mold structure having a plurality of article molds disposed in an array with an open central portion and a gating system extending across an upper end of the open central portion of the array of article molds is disclosed in U.S. Pat. No. 3,690,368 issued Sept. 12, 1972 and entitled Casting Single Crystal Articles. This patent teaches that thermal gradients within a mold structure and the rate of solidification of molten metal can be controlled by surrounding the article molds with the metal which is being cast. The forming of the cavities which surround the article molds complicates the making of the mold structure. In addition, the filling of the cavities surrounding the article molds with molten metal increases the quantity of molten metal required to cast articles.
The use of a baffle plate to retard the transfer of heat from article molds is disclosed in U.S. Pat. No. 3,714,977 issued Feb. 6, 1973 and entitled Method and Apparatus for the Production of Directionally Solidified Castings. The baffle plate is in the form of an annular disk and has an inner edge which surrounds and closely fits the mold structure at a location adjacent to a chill plate upon which the mold structure is supported. When the chill plate and mold structure are lowered from a furnace, the baffle plate engages flanges connected with the furnace and remains stationary during continued lowering of the chill plate and mold structure.
A method and apparatus for use in casting a plurality of articles in a mold structure having a plurality of article molds disposed in an array with an open central portion is disclosed in U.S. Pat. No. 3,810,504 issued May 14, 1974 and entitled Method for Directional Solidification. The apparatus disclosed in this patent includes an annular chill plate. A baffle plate is disposed in a central portion of the array of article molds to retard the transfer of heat from the article molds to the chill plate. After the article molds have been filled with molten metal, the chill plate is lowered relative to the stationary baffle plate to withdraw the mold structure from a furnace. The baffle plate is supported by an inner heat sink which extends upwardly through the central portion of the annular chill plate to support the baffle plate during the pouring of molten metal into the mold structure and subsequent withdrawal of the mold structure from the furnace.
A mold structure having a plurality of article molds disposed in an array with an open central portion and having a gating system extending across an upper end of the open central portion of the mold structure is disclosed in Patent Cooperation Treaty International Application No. PCT/US86/00166 filed Jan. 28, 1986 and entitled Method and Apparatus for Casting Articles. This application discloses the concept of obtaining a large temperature gradient with a baffle plate which blocks the radiation of heat from the open central portion of the array of article molds as they are withdrawn from a furnace. The baffle plate is supported by a gating system which conducts molten metal to the article molds. The gating system is connected with a furnace so that during withdrawal of the article molds from the furnace, the baffle plate is supported in the central portion of the annular array of article molds.